<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>小米</title>
    <style>
        .container {
            width: 800px;
            height: 500px;
            margin: 0px auto;
        }

        .left {
            float: left;
            height: 100%;
            padding-top: 20px;
            box-sizing: border-box;
            width: 200px;
            background: rgb(102, 97, 97);
            position: relative;
        }

        .left li {
            height: 40px;
            text-indent: 30px;
            font-size: 14px;
            color: #fff;
            line-height: 40px;
        }

        .left li:hover {
            cursor: pointer;
            background: orangered;
        }

        .left li .title {
            float: left;
            width: 150px;
        }

        .left li .layer {
            width: 500px;
            color: #000;
            height: 500px;
            background: #ada;
            position: absolute;
            left: 100%;
            top: 0px;
            display: none;
        }

        .left li:hover .layer {
            display: block;
        }

        .arrow {
            width: 5px;
            height: 5px;
            margin: 15px;
            border: 3px solid #ccc;
            border-color: #ccc #ccc transparent transparent;
            transform: rotate(45deg);
            float: right;
        }

        .right {
            float: right;
            height: 100%;
            width: 600px;
            background: red;
        }

        * {
            margin: 0px;
            padding: 0px;
            list-style: none;
        }

        .menus {
            width: 800px;
            height: 100px;
            margin: 10px auto;
            background: #ada;
            padding-top: 35px;
            box-sizing: border-box;
        }

        .menu-item {
            height: 30px;
            width: 80px;
            line-height: 30px;
            text-align: center;
            background: red;
        }

        .menus .layer {
            width: 100vw;
            height: 0px;
            background: orange;
            left: 0;
            position: absolute;
            z-index: 9;
            transition: 0.2s;
        }

        .menus:hover .layer {
            height: 200px;
        }
    </style>
</head>

<body>
    <a href="demo.html">demo1</a>
    <a href="demo1.html">demo2</a>
    <a href="demo2.html">demo3</a>
    <img src="cloud.jpg" alt="">
    <div class="menus">
        <div class="menu-item">
            小米手机
            <div class="layer"></div>
        </div>
    </div>


    <div class="container">
        <ul class="left">
            <li>
                <div class="title">手机电话卡</div>
                <div class="arrow"></div>
                <div class="layer" style="background:yellow">11111111111</div>
            </li>
            <li>
                <div class="title">家电数码</div>
                <div class="arrow"></div>
                <div class="layer" style="background:orange">22222222222</div>
            </li>
            <li>
                <div class="title">手机电话卡</div>
                <div class="arrow"></div>
                <div class="layer" style="background:#eee">33333333333333</div>
            </li>
            <li>
                <div class="title">手机电话卡</div>
                <div class="arrow"></div>
                <div class="layer"></div>
            </li>
            <li>
                <div class="title">手机电话卡</div>
                <div class="arrow"></div>
                <div class="layer"></div>
            </li>

        </ul>
        <div class="right"></div>
    </div>
</body>

</html>